The present invention relates to providing previews of routes calculated with navigation systems used for vehicles that travel on roads.
Navigation systems are available for vehicles (such as automobiles, trucks, buses, and so on) that travel on roads. These in-vehicle navigation systems provide end users (such as drivers and/or passengers of the vehicles in which the navigation systems are installed) with various useful navigation-related features. For example, some navigation systems are able to determine an optimum route to travel by roads between locations in a geographic region. Using input from an end user and optionally from equipment that can determine one's physical location (such as a GPS system), programming in the navigation system can examine various routes between two locations to determine an optimum route to travel from a starting location to a destination location in a geographic region. The navigation system may then provide the end user with information about the optimum route in the form of instructions that identify the driving maneuvers required to be taken by the end user to travel from the starting location to the destination location. The instructions may take the form of visual and/or audio instructions that are provided along the way as the end user is traveling the route. On computer displays that are part of the navigation system hardware, some navigation systems are able to show detailed maps highlighting routes to destinations, the types of maneuvers to be taken at various locations along the routes, locations of certain types of features, and so on.
In order to provide these types of features, navigation systems use geographic data. The geographic data may be in the form of one or more databases that include data that represent physical features in a geographic region. The geographic databases may include data representing the roads and intersections in a geographic region and also may include information relating to the represented roads and intersections, such as turn restrictions at intersections, speed limits along the roads, street names of the various roads, address ranges along the roads, and so on.
Although navigation systems provide many important features, there continues to be room for improvements. One area in which there is room for improvement relates to providing a route preview feature. A route preview feature provides the end user with a preview of a calculated route. The preview may consist of an outline or summary of the calculated route. The outline or summary may include the names of the roads in the calculated route as well as a limited amount of other information. The route preview may be displayed or otherwise provided to the end user as text or graphically. The route preview does not include detailed maneuvering instructions for driving the route.
The route preview is presented to the end user just after the route has been calculated by the navigation system but before the end user has traveled far along the route. A preview of the calculated route affords the end user an opportunity to become familiar with the route in general before embarking on traveling the route. Some navigation systems may afford the end user a chance to reject the calculated route or possibly to modify the calculated route when the route preview is presented. For example, the end user may want to avoid a road in a calculated route known to have heavy traffic, construction delays, etc. Based upon the information in the route preview, the end user may request the navigation system to calculate an alternative route. Even if the end user does not request an alternative route, the end user may be more comfortable knowing the roads in the calculated route in advance of traveling the calculated route. Thus, providing the end user with a preview of a calculated route before the end user travels along the route can be a useful and desirable feature.
Although a route preview can be a desirable feature, it can be difficult to provide with some navigation systems. Some navigation systems have relatively limited computing resources, such as relatively limited memory, relatively slow I/O, relatively slow processors, etc.
One way to provide a route preview with a navigation system is to extract the names of the roads or other details from the maneuvering instructions generated by the route guidance function of the navigation system. As mentioned above, some navigation systems include a route guidance function that provides the end user with visual and/or audio maneuvering instructions that identify the maneuvers required to travel along the calculated route from the starting location to the destination location. The maneuvering instructions generated by the route guidance function may be very detailed, and accordingly substantial computing resources of the navigation system may be needed for generating and providing the maneuvering instructions. However, the maneuvering instructions are provided one at a time as the route is being driven. Thus, even a navigation system with relatively modest computing resources can provide an end user with rich, detailed maneuvering instructions because a relatively large amount of time is available to generate and provide the maneuvering instructions.
This aspect of the route guidance function can make it difficult to use the data from the maneuvering instructions generated by the route guidance function to provide a preview of the calculated route. Since the data which are needed for a route preview (i.e., names of roads and possibly other information) are embedded in the relatively complex maneuvering instructions generated by the route guidance function, generating the maneuvering instructions and then extracting the information needed for the route preview from the maneuvering instructions can require substantial computing resources. If the navigation system has relatively limited computing resources, providing a route preview feature in this manner can be relatively slow. Since a purpose of the route preview feature is to allow the end user to evaluate whether to accept the calculated route before embarking on the route, it is important that the route preview function operate relatively quickly even on navigation systems with limited resources. Thus, there is a need to provide a route preview function that operates quickly even on navigation systems with limited resources.
Some in-vehicle navigation systems have greater computing resources, e.g., more memory and faster I/O. Users of these types of in-vehicle navigation systems can also benefit from improvements that enable a preview of a calculated route to be generated quickly.
Navigation-related information and features can be provided on computing platforms other than in-vehicle navigation systems. Navigation application programs that provide navigation-related features are available on various kinds of computer hardware platforms and with various kinds of computer architectures. For example, navigation application programs may be provided on personal computers, including desktop computers and portable computers. Navigation application programs may also be provided on distributed systems, such as networks, including wireless networks and the Internet. Navigation application programs may also be included on hand-held computer devices, such as personal digital assistants, telephones, pagers, PalmPilot.RTM.-type devices, and so on. In addition, navigation application programs may be included on special purpose electronic devices, such as personal navigation systems. Users of navigation application programs installed on these types of platforms and systems can also benefit from improvements that enable a preview of a calculated route to be generated quickly.
Thus, there is a need to provide a route preview function with a navigation system or a navigation application program. There is also a need to provide a route preview function that operates quickly even on computing platforms that have relatively limited resources.